The know-how information to perceive care needs based on assessment results is crucial to improve the quality of care service. We developed a know-how information sharing system for care planning processes. We propose a method that externalizes and shares know-how information by visualizing and observing care plans drawn by experts in various forms that allow beginners to notice the differences between the plans of novices and experts. Sharing know-how information is possible by recording, accumulating, and referring to what has been observed when comparing documents. This system two-dimensionally maps and visualizes each document based on the differences among documents perceived by the assessment results. Externalizing and sharing know-how information are supported by visualization. Trial results in a care facility confirmed that our system effectively externalized and shared know-how information. Improvement in individual capabilities, organization growth, and the possibility of rejuvenation were confirmed by using our system.